In a standard air compressor, the compressed air is completely saturated with water vapor as it leaves the final stage of compression. Air thus compressed must be cooled to be of further use, for example in pneumatic tools. The cooling step always produces a condensate when the saturated moist air is passed through an after-cooling device or coil, with the condensate forming on the inside surface of such device current practice is to discard such condensate.
Cooling and drying compressed air is a major expense, both in the initial investment in equipment, and in the continuing costs of energy to operate it. Some systems employ an air-cooled aftercooler, like a large radiator, with compressed gas inside, and outside air passing between the coils. Some use a refrigerated dryer, a chiller system having a refrigeration circuit, which cools and then reheats compressed air to reduce its moisture content. Other systems may use a combination of both an aftercooler and a refrigerated dryer. Sometimes even the compressor itself is cooled, by passing air over cooling fins mounted on it, or by an air cooled water system which functions like the radiator on an automobile engine.
In addition to greatly reducing the cost of operating such equipment, the present invention provides a significant environmental benefit. The condensate may be entirely consumed in the operation of the system, eliminating the need to treat it upon discarding. Moreover, there may be no need to use water from outside the installation for cooling, since the condensate alone may suffice for that purpose.